Motor problem 350 marine power

[intimidator3]

We have a 1994 29 Luhrs open and the port side motor is running an unusually high rpm. Paid a boat mechanic to fix but the problem persists. I tried replacing the IAC on the throttle body but that didn't make a difference. Have been running startron in the fuel but i can't seem to solve the rpm problem. Some days it runs just above normal at 650 rpm but after our last trip got back to the dock and it wouldn't idle below 1100 rpm. It goes up as soon as the motor is started. The motors are well taken care of and only have 510 hours. Any help would be great. Thanks.

[CrazyIslandMoFo]

Are your motors EFI... a simple device to plug into the electrical harness, Code reader, two blinking lights 1 blink then two blinks..code twelve all good .The computer will hold any trouble codes. Maybe a start... My motors went through a spat of a "high idle" just after cold starts, I changed all cap,rotor,plugs. Haven't notced since... now they're a little fussy when they're hot... :dunno: also check linkage... My starbord motor is still burning a noticable amount more gas than port, one source said the engine temp sensor may be bad and the computer is trying to cool the block by dumping gas...:banghead: not so obious.